Within the petroleum industry, crystallization, and wax deposits can occur within upstream or downstream operations. Paraffin wax is most commonly used to describe this type of deposit. Paraffin wax is commonly comprised of long, straight or branched alkane compounds in the range of C18H38 to C60H122 that are naturally present in crude oils.
Paraffin wax is usually soluble in crude oil under “down-hole” conditions. Ordinarily, as the crude oil is brought to the surface, its temperature is reduced and the crude oil is subjected to a diminished pressure. As the crude oil leaves the wellhead at the reduced pressure, dissolved gases, which act as natural solubilizers for paraffin wax, tend to come out of solution. These two factors, the decrease in temperature and the loss of dissolved gases, decrease the ability of the remaining crude oil to keep the paraffin wax in solution. As a result, wax crystals may precipitate on any appropriate surface.
When the paraffin waxes precipitate, they cause a myriad of problems for the oil producer. These deposits can cause numerous problems including blocking pores in near-well formations, production tubing, and downstream pipelines, cause a reduction or plugging of pipework, increase fluid viscosity, reduce operational efficiency, create a safety hazard, and associated disposal problems when the deposits are removed. Further, these deposits can create flow restrictions by depositing or accumulating downhole on tubing, rods, and sub-surface pumps; and above ground in valves, piping, separators, and storage tanks. Additionally, these deposits can also increase fluid viscosity, increase operating cost as efficiency is decreased, and also reduce pump efficiency. These troublesome deposits are combinations of an array of molecular weight hydrocarbons and adsorbed impurities.
There are numerous ways to control wax formation and deposits in upstream and downstream operations. Additives can be added to interfere with the crystallization process of the wax and suspend wax crystals in the oil. However, these additives can be complicated to manufacture and are often difficult to formulate into a crude oil treatment product.
Therefore, a need exists to develop simple molecules that function to inhibit paraffin wax formation and deposition.